I Have Alot of Sadness In My Heart

I often wonder what that point was in my life where I made the wrong decision to cause everything to fall apart. I've watched all the people around me in my life accomplish things, find happiness and love. It all seems to elude me. I don't blame anyone else for that, no one's fault but my own. Perhaps I just am not able to be happy. I have no drive or focus in my life. Every time I seem to find myself at a point where I think i'm happy, it all comes crashing down.